Phase-locked loop based on equivalent phase demodulation frequency

Abstract

The invention relates to a phase-locked loop, in particular to a phase-locked loop based on equivalent phase demodulation frequency. The phase-locked loop is characterized by at least comprising a detected signal frequency divider, a reference signal frequency divider, a phase demodulation processing module and a voltage controlled oscillator, wherein the detected signal frequency divider and thereference signal frequency divider are used for frequency division for a detected signal and a reference signal to make the equivalent phase demodulation frequency of the detected signal and the reference signal which are acquired by the frequency division be 5 MHz; the phase demodulation processing module finishes the phase demodulation of a signal of the detected signal passing through the frequency divider and a signal of the reference signal passing through the frequency divider, and outputs a control voltage for controlling the voltage controlled oscillator; and the voltage controlled oscillator is used for controlling oscillation signals output by the voltage. The frequency division values of the detected signal frequency divider and the reference signal frequency divider are controlled by an external singlechip, and the singlechip inputs the needed frequency division values into the frequency dividers in form of 8bit data. The voltage controlled oscillator is a voltage controlled crystal oscillator of 5MHz, an input end of the oscillator is electrically connected with an output end of an amplifying and shaping module, and an output end of the oscillator is electrically connected with an input end of the detected signal frequency divider.

Description

technical field [0001] The invention relates to a phase-locked loop, in particular to a phase-locked loop based on an equivalent phase-discrimination frequency. Background technique [0002] At present, the phase-locked loop technology used at home and abroad has such characteristics: use the reference signal to control the frequency and phase of the loop oscillating signal, so that the oscillating signal can track the frequency and phase of the reference signal. When the frequencies of the two are completely equal, the considered locked. This phase-locked loop circuit can be divided into three types, namely, analog phase-locked loop (APLL), digital phase-locked loop (DPLL) and software phase-locked loop with memory capability (microcomputer control). A phase-locked loop usually consists of three parts: a phase detector (PD), a loop filter (LF) and a voltage-controlled oscillator (VCO). The traditional analog phase-locked loop (APLL) has a short locking time to ensure the ...

AI Technical Summary

Problems solved by technology

The traditional method uses a lot of frequency multipliers and mixers to expand the locked frequency range, which makes the phase-locked equipment complicated, expensive, and unreliable

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